Dam removal

On Vacation with EPA Science

By Elizabeth Blackburn

Rafting (lge)My family is always giving me a hard time about the difficulty I seem to have completely disconnecting from work. Not only does my ever-present, e-mail-spewing smartphone mean I can keep in touch with my colleagues from virtually any location and at any time, but my job can be really interesting!

As the director of science communications for EPA’s Office of Research and Development, I get a firsthand look at just about every science story that flows from the Agency’s world class scientists and engineers, as well as from a partnership community uniting EPA researchers and other innovators from across the government, academia, business, and beyond. I get a “sneak peak” at an incredible breadth of stories covering everything from tiny nanoparticles, to children’s environmental health, ecosystems assessment, and global climate change adaptation.

With all that going on, you can understand why I find it hard to unplug. Even so, I made a commitment to do my best on a recent family trip. I traveled clear across the country with my husband to visit our son, who lives in the “other” Washington (Washington State).

There, thousands of miles from the office, surrounded by some of the best rafting opportunities anywhere in the world, I came across something that brought my mind right back to work: dam removal. That’s something that our scientific divers have been blogging about right here on It All Starts with Science.

Dam removal has a special place in my heart as there was a dam removed on the river my son—a rafting guide—works on. In fact, we rafted a portion of the White Salmon that had been previously underwater. The canyon was magnificent and it was awesome to see steelhead trout swimming upstream and jumping up waterfalls that they had previously been unable to reach because of the dam.

So, not only did I get to enjoy a somewhat harrowing raft trip with my family, but I got to share what I do and why I like it with a captive audience. For those of you who didn’t have the opportunity to join us on the raft, check out this morning’s blog from our scientific divers about their latest observations and findings. It answers some of the same questions I had about dam removal and what they are learning.

While I’d love to share more about my family vacation and the glorious Pacific Northwest, I’ve got to get back to work. (Oh goodie!)

About the Author: Elizabeth Blackburn is the Director of Communications for EPA’s Office of Research and Development, and an avid fan of wild and scenic rivers anywhere.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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What’s changed? Post dam removal benthic surveys start at the mouth of the Elwha River

By Sean Sheldrake, Steve Rubin, and Alan Humphrey

Tube worms

Schizobranchia insignis tubeworms, Photo by Sean Sheldrake, USEPA.

In this second part of our story (see our earlier blog post), we return to the Elwha to talk more about the techniques involved with the survey.

This USGS-led survey involves counting over 65 species of invertebrates and 23 species of algae—all of which we had to memorize before the survey began.  As if that wasn’t enough homework for the dive crews, you have to “sneak” up on your critters to actually count them!

Species like Mya truncata clams can “see” you coming and will retract if they can feel the pressure wave of the diver approaching.  Likewise, tubeworms are also underwater detectives with their own early warning sensors for approaching divers.  Once Schizobranchia insignis or Eudistylia polymorpha tubeworms retract they look remarkably similar!

In buddy teams, divers go down and count algae (kelp, for example) on one side of the transect, and invertebrates (such as clams) on the other.  Our divers must adjust for this “shy” behavior when they reach the bottom and “change things up.”   Since each diver must count critters and algae on one side of the transect only, the invertebrate scientist tries to count on the downcurrent side of the transect line.  After all, the algae-counting scientist has the benefit of their “prey” not running away from them!

Diver along a transect

EPA diver Scott Grossman conducts a uniform point count along a straight line "transect" placed on the ocean floor. Photo by Alan Humphrey, USEPA.

In addition to counting all the species within one meter of the transect tape for 30 meters for algae and invertebrates respectively, a separate survey is done called a “uniform point count.”  Every ½ meter, the diver puts their finger down along the transect tape and counts only what is beneath it. (Even if the most amazing anemone is an inch away, it doesn’t count!) Statistically, the point count and overall tally of species will give a representative assessment of life in the ocean ecosystem near the Elwha River mouth.

Early survey results included a decrease in algae abundance compared to levels seen before the start of dam removal.  The decrease may have been due to light deprivation rather than loss of suitable substrate as there was little obvious accumulation of sand or mud on the seafloor.  The divers deployed light sensors at many stations to help to document what sort of change in light penetration was occurring at each site.  In addition, it seems that tubeworms are on the increase.

What other changes are there?  The study will show the changes for the nearly 100 species of algae and invertebrates, in addition to fish, for the largest dam removal effort in North America to date.

Find out more about the wild survey conditions next week in part three of our story.

For more information on the study, see: http://www.usgs.gov/elwha.

For more information about the EPA dive program, check out their Facebook page at: http://www.facebook.com/EPADivers.

About the authors: Sean Sheldrake is part of the Seattle EPA Dive unit and is also a project manager working on the Portland Harbor cleanup in Oregon.  He and Alan Humphrey both serve on the EPA diving safety board, responsible for setting EPA diving policy requirements.  In addition, they both work to share contaminated water diving expertise with first responders and others.  Steve Rubin is an aquatic biologist specializing in algal species with the USGS and a lead scientist on the survey.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Diving in the Silt Plume of the Elwha River

By Chad Schulze, Steve Rubin, and Sean Sheldrake

Mouth of the Elwha River

Overlooking the mouth of the Elwha River.

Some of you may have followed our previous blog posts about EPA’s scientific diving program in It’s Our Environment, but we also wanted to share some recent work led by U.S. Geological Survey (USGS) and supported by EPA divers near the mouth of Washington State’s Elwha River here in It All Starts with Science.

Now that removal of the Elwha River dams is well under way, USGS scientists, assisted by divers with the Lower Elwha Klallam Tribe, EPA, and Washington Sea Grant, will continue studying the impacts of removal-related sediment to the Strait of Juan de Fuca.

As the first EPA crew to visit the site this year, we didn’t know what to expect.

What we did know—the removal of the Elwha River dams will affect marine habitats in the Strait of Juan de Fuca, primarily from the flow and deposition of released sediment that had accumulated behind the dams for nearly 100 years. That sediment can affect marine life in many ways, including: burial, reduced aquatic reproduction, shading and light reduction, damage to animal gills and filter feeding structures, and changing how different species behave individually and together with their different tolerances and responses to the sediment.

EPA Scientific Diver

Diver Steve Rubin, USGS shooting video of a transect to compare to baseline conditions.

Diving in on the first day, we found the conditions to be very different from before the dams were in place—last year visibility might be up to 50 feet!  Not so this year, with some freshwater layers discharging from the Elwha with maybe 6 inches of visibility.

As we descended through this floating “halocline” of different salinity layers (less dense freshwater will sometimes float over the ocean saltwater until it mixes), it was like a “cloud” over the saltwater below.  Visibility improved when we made it through, but it was DARK.  Where last year the sun was sometimes visible on the seafloor, this year, we needed lights to see the bottom.

Things have changed. For starters, where there had been algal forests, we found much less growth compared to last year. We and our partners will continue to survey Elwha nearshore undersea communities during and after dam removal.  Measuring responses to short and long term changes in deposited and suspended sediments offers an unprecedented opportunity to gain insight relevant to managing these important marine resources, and will help to inform how future dam removal projects can be conducted to minimize impact to downstream plants, insects, fish and animals.

For more information on the study, please see this story on the USGS web site: http://walrus.wr.usgs.gov/elwha/

We’ll follow up with another post as we continue to work. Stay tuned!

About the authors:  Sean Sheldrake and Chad Schulze are part of the Seattle EPA Dive unit.  Chad is the lead pesticide enforcement in the Northwest, and Sean is also a project manager working on the Portland Harbor cleanup in Oregon.  Steve Rubin is an aquatic biologist specializing in algal species with the USGS and a lead scientist on the survey.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.